So you've got a rifle, a pile of associated crap, and an objective to hit. Rather than trying to hang all that stuff off your belt, putting all the weight on your hips, you could use a chest rig. Current industry offerings can carry from two to eight magazines worth of ammunition, plus radios, first aid kits, administrative supplies, maps, chemlights, batteries, snacks, and so on. Putting all this stuff into the rig and slinging your rifle, you can get to work.
In the past, load-bearing equipment has generally been belt-based, with suspenders or full vests being seen as weight increased. Interestingly, it was the Chinese communists who developed an alternate solution in the form of the Type 56, or Chicom chest rig. A hexagonal piece of cloth with three magazine pouches in the center and two grenade pouches on each side, it is worn across the chest and secured in place by straps going over the user's shoulders. The Soviet Union would make a modified copy of this and use it extensively in Afghanistan, referring to it informally as "liftchik", or bra.
US special forces would use Type 56 chest rigs in Viet Nam, and eventually the rest of the military would see the utility of chest rigs as well, ironically also in Afghanistan. At this point, the commercial market in the US took over. After a few years, veterans of the conflict would begin to sell their own products based on their own experiences, which brings us to the chest rig I typically use for shooting.
The Haley Strategic D3CR, or Disruptive 3nvironments Chest Rig (yes, 3nvironments. I don't know either.) adheres to a simple but effective formula: 4mag2gp, or four magazines, two general purpose pouches. The four cells each hold a single magazine for an AR-15/M-16 type rifle, and the two general purpose pouches do as the name suggests and hold a variety of things. On mine, I have a first aid kit in one and administrative supplies in the other. Centered on the front between the two general purpose pouches are two pistol magazine pouches and a clever resizeable stuff-it pocket. I keep a radio in that one. This isn't a huge amount of stuff, but it provides enough logistical support for short missions in quite a small package.